Control Module For A Powered Surgical Tool

ABSTRACT

A control module for a powered surgical tool. The module includes a shell. Internal to the shell is a circuit for controlling the power generating unit of the tool with which the module is associated. Conductive pins extend through the shell to provide electrical connections to the components within the shell. Active seals are disposed around the conductors and the inner walls of the shell that define the openings in which the pins are seated. Each active seal include an inner and outer skirt. A biasing component disposed between the skirts urges the inner skirt against the section of the conductive pin seated in the opening. The biasing component also urges the outer skirt against the adjacent opening-defining inner wall of the shell. The active seal functions as a barrier between the conductive pin and the adjacent inner wall of the shell.

RELATIONSHIPS TO EARLIER FILED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/057,649 filed 1 Mar. 2016. U.S. patent application Ser. No.15/057,649 is a divisional of U.S. patent application Ser. No.13/922,877 filed 20 Jun. 2013, now U.S. Pat. No. 9,295,476. U.S. patentapplication Ser. No. 13/922,877 is a continuation of PCT App. No.PCT/US2011/066226 filed 20 Dec. 2011. PCT App. No. PCT/US2011/06226claims priority from U.S. Prov. Pat. App. No. 61/425,523 filed 21 Dec.2010. The contents of the above-identified applications are incorporatedherein by reference.

FIELD OF THE INVENTION

This invention is generally related to electrically powered surgicaltools. More particularly, this invention relates to a powered surgicaltool with a sealed control module in which the circuit that controls theactivation of the tool is enclosed.

BACKGROUND OF THE INVENTION

In modern surgery, one of the most important instruments available tomedical personnel is the powered surgical tool. Often this tool is inthe form of a handpiece in which a motor is housed. Secured to thehandpiece are cutting accessories designed for application to a surgicalsite to perform a specific medical procedure. For example, some poweredsurgical tools are designed for use with cutting accessories such asdrills, burs or reamers for cutting bores into tissue or for selectivelyremoving tissue such as bone. Other powered surgical tools are providedwith saw heads. These tools are designed to be used with saw blades orblade cartridges used to separate large sections of hard and softtissue. A wire driver is a power tool that, as its name implies, drivesa wire into a patient, more particularly, a bone. Power tools are alsoused to perform other functions in the operating room. For example, itis known to use a power tool to mix the components that form a mass ofsurgical cement.

The ability to use powered surgical tools on a patient lessens thephysical strain of surgeons when performing medical procedures on apatient. Moreover, most surgical procedures can be performed morequickly and more accurately with powered surgical tools than with themanual equivalents that preceded them.

One type of powered surgical tool that is especially popular with somephysicians is the cordless, battery-operated powered surgical tool. Asthe name implies, this tool has a battery that serves as the powersource for the motor. This eliminates the need to provide the tool witha power cord connected to an external-power source. Elimination of thepower cord offers benefits over corded, powered surgical tools. Surgicalpersonnel using this type of tool do not have to concern themselves witheither sterilizing a cord so the cord can be introduced into the sterilesurgical field or ensuring that, during a procedure, an unsterilizedsection cord is not inadvertently introduced into the surgical field.Elimination of the cord also results in the like elimination of thephysical clutter and field-of-view blockage a cord brings to a surgicalprocedure.

One feature shared by both corded and cordless power surgical tools isthe presence of a control switch or member on the tool. This member isoften in the form of a biased switch, trigger or button. A number ofcorded and cordless surgical tools have handles similar to pistolhandgrips. A tool of this shape is sometimes designed so that thecontrol member is a trigger that is slidably mounted with respect to thehandle.

Surgical power tools, unlike many other conventional power tools, haveto do more than deliver relatively large amounts of power. Surgicalpower tools must also be compliant with government regulatory agenciesand hospital operating room standards for medical surgery. Surgicalpower tools must be able to withstand repeated exposure to anenvironment that is saturated with steam and an environment that is veryhot. This is because, prior to use, a powered surgical tool is autoclavesterilized. In this process, the tool is placed in a chamber where theatmosphere is saturated steam, the temperature is approximately 135° C.(or 275° F.) and the atmospheric pressure is approximately 207,000 Pa(or 30 psi). Internal components of the tool, including the conductive,electrical components of its control circuit, if left unprotected in andrepeatedly exposed to this environment, can corrode or short circuit. Acommon solution is to have a sealed control module to enclose theseinternal electrical components in a welded or brazed housing. A problemexists because during the sterilization process these housings arerepetitively exposed to both pressurized steam and a vacuum environment.This cyclic pressurizing and depressurizing of the control module causesthe walls or panels of the module to repetitively bulge in and out. Thisrepetitive flexure of the module walls/panels results in a fatiguedfailure of the weld/braze. As a consequence of this failure, steam canenter the module.

The Applicant's Assignee's U.S. Pat. No. 7,638,958, POWERED SURGICALTOOL WITH CONTROL MODULE THAT CONTAINS A SENSOR FOR REMOTELY MONITORINGTHE TOOL POWER GENERATING UNIT, issued Dec. 29, 2009, and incorporatedherein by reference, discloses one means for protecting the internalcomponents of a surgical power tool from the affects of autoclavesterilization. The tool of this invention has a sealed module thathouses the control circuit that regulates tool actuation. The controlcircuit regulates the actuation of the power generating unit of thesurgical tool. The power generating unit emits a signal representativeof its operating state. Inside the sealed control module shell is asensor that monitors the signal emitted by the power generating unit.The control circuit, based on the sensor signal, regulates actuation ofthe power generating unit. Where the power generating unit is a motor,the signal emitted by the unit is the magnetic field that varies withrotor position. The sensor monitors the strength of this field.

U.S. Pat. No. 5,747,953 also discloses a means for protecting theinternal components of a surgical tool from the affects of autoclavesterilization. The tool of this invention has a sealed module thathouses the circuit that regulates tool actuation. Also internal to thismodule, are contactless sensors that monitor the states of externallymounted triggers. Attached to each trigger and located inside the toolhousing is a magnet. Internal to the module are magnetic field sensors.Each sensor generates a varying signal as a function of the proximity ofan associated one of the trigger magnets. The manual displacement of thetrigger results in a like displacement, inside the tool, of the magnet.When a trigger and magnet are so displaced, the complementary sensorgenerates a signal that indicates the movement has occurred. Uponreceipt of this signal, the control circuit generates the signal neededto allow an energization current to be applied to the motor.

The electrically conductive components of the on/off control assembly ofthe above tool are shielded from the supersaturated steam of theautoclave environment. When this tool is sterilized, these componentsare not adversely affected.

The control modules of the Applicant's Assignee's U.S. Pat. Nos.5,747,953 and 7,638,958, both of which are incorporated herein byreference, have proven to be useful for shielding the tool controlcomponents and sensors from the effects of autoclave sterilization.However, the modules of both these patents include a housing that isessentially a shell to which a lid is brazed. During the sterilizationprocess, the high pressure vapor imposes a significant pressure on themodule housing. This force is known to press, or flex, the panels of themodule shell and lid inwardly. Once the pressurized gas is removed fromthe chamber in which the tool is being sterilized, the gas within themodule, which was compressed by the inward flexing of the panels formingthe housing, flexes the panels outwardly to their initial state. Thisrepeated in and out flexing of the housing lid weakens the braze thatholds the lid to the complementary shell. This weakening of the brazejoint can result in its separation. Once the braze separates, steam isable to flow into the module housing. This steam, when it condenses aswater, collects on the components internal to the module. This water cancorrode or short circuit the components internal to the module so as torender the module itself useless.

Moreover, even the panels of the module of Applicant's Assignee's U.S.Pat. No. 7,638,958 are formed with openings. Plural sets of contact pinsextend into this module. A first set of pins function as the conductivepaths over which power signals are applied to the module. A second setof conductive pins function as the conductive paths over which thecontrol components internal to the module selectively apply energizationsignals to the power generating unit integral with the tool. A third setof pins are used to exchange data and control signals with componentsexternal to the module. These pins extend through openings in the modulehousing.

Presently, powered surgical tools utilize ceramic frits to seal theopenings of the module housing through which these pins extend. Each fitextends between a pin and the internal wall of the module housing thatdefines the opening through which the pin extends. Often these frits aretubeshaped. These ceramic frits can withstand the rigors of autoclavesterilization. While these frits provide good seals, they are expensiveto manufacture.

SUMMARY OF THE INVENTION

This invention is related to a new and useful powered surgical tool witha control module designed to withstand the rigors of autoclavesterilization. The surgical tool of this invention is designed toprovide an internal circuit board, which is sealed so as to avoidmalfunction caused by sterilization.

The powered surgical tool of this invention includes a handpiece thatcontains the power-producing component. Often this component is a DCmotor. Also, internal to the handpiece is a module that contains thecontrol circuit that regulates the application of power to the motor.This control circuit is contained in a sealed module.

The components internal to the sealed control module are shielded fromthe outside environment using active seals. Active seals act as sealingagents around the pins that enter the holes found on the control modulehousing. An active seal comprises a boot and a spring that collectivelyform a substantially gas-tight seal between the interior of the controlmodule housing and the external environment. Pins enter through a seriesof holes found on a single panel of the module housing and into theinside of the control module housing. Active seals are relativelyinexpensive to provide.

The control module of this invention further includes a shell to which alid is attached. A threaded fastener holds the lid to the shell. One ormore O-rings are disposed between the lid and the shell. The O-ringsform a substantially gas-tight seal between the lid and the shell. TheO-rings are able to withstand the rigors of autoclave sterilization.

In one embodiment, the powered surgical tool of this invention is acordless tool. In other embodiments of this invention, the tool iscorded.

Another feature of the tool of this invention is that active seals aredisposed around the conductive pins that extend through the modulehousing. Each active seal functions as a barrier between the pin withwhich the seal is associated and the inner wall of the housing thatdefines the opening through which the pin extends.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is pointed out with particularity in the claims. The aboveand further features of this invention may be better understood byreference to the following description taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a side view of a powered tool incorporating the features ofthis invention;

FIG. 2 is a cross sectional view of a powered tool of this invention;

FIG. 3 is a perspective view of the sealed control module with sealassembly;

FIG. 4 is a plan view of the top of the control module with sealassembly;

FIG. 5 is an exploded view of the control module illustrating some ofthe components mounted to and in the module;

FIG. 6 is a plan view of the control module shell without lidillustrating the step for the outer O-ring and the post for the innerO-ring;

FIG. 6A is a plan view of the lower panel of the control moduleillustrating the bore holes that accept the seal assembly

FIG. 7 is a plan view of the bottom of the control module lid;

FIG. 8 is a cross sectional view along the long axis of the controlmodule illustrating the control module lid and shell, fastener, pins,outer retaining cap, inner retaining cap and active seals;

FIG. 9 is a cross sectional view across the short axis of the controlmodule illustrating the control module lid fastened to the shell using afastener;

FIG. 10 is an exploded view of the seal assembly illustrating the pins,the outer retaining cap, the active seals, and inner retaining cap;

FIG. 11 is a side view of the pin illustrating the separate sections ofvarying diameter along the long axis of the pin shaft, and the D-shapedpin collar;

FIG. 12 is a plan view of the back of the pin illustrating the D-shapedpin collar;

FIG. 13A is a perspective view of the outer retaining cap;

FIG. 13B is a plan view of the outwardly directed face of the outerretaining cap;

FIG. 13C is a plan view of the inwardly directed face of the outerretaining cap;

FIG. 14A is a perspective view of the inner retaining cap;

FIG. 14B is a plan view of the inwardly directed face of the innerretaining cap;

FIG. 14C is a plan view of the outwardly directed face of the innerretaining cap;

FIG. 15 is a cross sectional view of the control module illustrating themodule shell together with the finished seal assembly inserted withinthe module shell, the seal assembly illustrating each pin, active seal,outer retaining cap and inner retaining cap;

FIG. 16 is a plan view of the lower panel of the control moduleillustrating the finished seal assembly within the module shell;

FIG. 17 is a perspective view of the control module shell illustratingthe two rows of staggered holes on the lower panel of the shell toaccept an active seal assembly;

FIG. 18 is a sectional view of an active seal illustrating a boot, and aspring disposed within the boot;

FIG. 18A is a sectional of view of an alternative embodiment of the sealassembly illustrating a stop integral with the active seal, and a springdisposed within the seal boot;

FIG. 18B is a sectional view of alternative stops that may be componentsof the seal assembly;

FIG. 19 is an exploded view of an alternative embodiment of the controlmodule illustrating some of the components mounted to and in the module,including: a mount, a plurality of Hall sensors, a circuit board and aspacer;

FIG. 20 is a perspective view of the mount;

FIG. 21 is a plan view of the mount from the front, top, bottom andsides;

FIG. 22 is a plan view of the top of the spacer, and a perspective viewof the spacer;

FIG. 23 is a plan view of the circuit board illustrating a plurality ofbores; and

FIG. 24 is a plan view of an alternative embodiment of the controlmodule lid illustrating a plurality of recesses.

DETAILED DESCRIPTION I. First Embodiment

FIGS. 1 and 2 illustrate a power tool 30, a surgical tool, constructedin accordance with this invention. Tool 30 has a housing 32 in which anelectrically-actuated power-generating unit is located. In the specifictool 30, this power-generating unit is a brushless, Halless, DC motor34. Tool housing 32 is shaped to have a generally cylindrical head 36 inwhich motor 34 is fitted. Extending downwardly from head 36, toolhousing 32 is shaped to have a handle 38. Handle 38 is formed to have aninternal void space 29. An attachment 31 extends from the housing 32that is connected to and actuated by the power generating unit 34 forperforming a surgical/medical task.

Also contained in the head 36 is a coupling assembly 39 represented by aring moveably mounted to the front part of housing 32. Coupling assembly39 consists of the mechanical linkage that releasably attaches asurgical attachment 31 to the motor 34 so that the motor can actuate theattachment 31. In some tool systems of this invention, the attachment isreferred to as a cutting accessory. The exact structure of the couplingassembly 39 is not relevant to the structure of this invention. If, asin the tool of FIGS. 1 and 2, the power generating unit is motor 34,coupling assembly 39 consists of a locking arrangement that releasablyholds the accessory to the motor shaft 27 so that accessory rotates oroscillates with the rotation of the motor shaft. In some versions of theinvention, a speed reduction gear assembly 28 is located between motor34 and coupling assembly 39.

Disposed inside the handle void space 29 is a sealed control module 40.Control module 40, as discussed below, contains the components thatregulate the application of energization current to the motor 34. Onecircuit that can be employed with this version of the invention isdescribed in the Applicant's Assignee's previously incorporated byreference U.S. Pat. Nos. 5,747,953 and 7,638,958.

Power for energizing the motor 34 is from a battery (not identified). Inpractice, the battery is removably attached to the butt end of thehandle 38. One battery that can be employed with this version of theinvention is described in the Applicant's Assignee's U.S. Patent App.Pub. No. 2007/0090788 published on Apr. 26, 2007, and hereinincorporated by reference.

Also shown in FIG. 1 are two trigger switches 46 and 47 arranged intandem extend forward from the front face of the handle 38. Each triggerswitch 46 and 47 is slidably mounted to the tool housing 32. Eachtrigger switch 46 and 47 includes a generally cylindrical barrel 50. Thebarrel 50 is the portion of the trigger switch 46 or 47 that extendsforward of the housing handle 38. Each trigger switch 46 and 47 has ahead (not identified), shaped as a fingerhold, and is disposed over thedistal free end of the barrel 50. (“Distal”, it shall be understoodmeans toward the surgical site to which the tool 30 is directed.“Proximal”, means away from the surgical site.) Trigger switches 46 and47 are mounted to tool housing 32 so that the barrels 50 are located infront and are aligned with the control module 40.

As shown in FIGS. 2, 3 and 4, a tab 50 is used to orient the controlmodule 40 within handle 38 of the tool 30. Tab 50 extendsperpendicularly outwardly from side panel 51 of control module 40. Thetab 50 is adjacent lower panel 53. The tab 50 is formed with an opening,not identified. Tab 50 serves as a bracket for receiving a fastener (notillustrated) used to hold the control module 40 in the handle 38.

Also shown in FIG. 3, are pins 75 that extend through the shell lowerpanel 53. The pins 75 provide electrical connections to the componentsinternal to module shell 58. A seal assembly 56 is located on the lowerpanel 53 for securing pins 75 to control module shell 58. Additionally,lid 60 sits on top of control module shell 58 and is secured to theshell 58 using a threaded fastener 55. Pins 75 extend perpendicularlyoutward from the lower panel 53 of module shell 58. Pins are securedwithin seal assembly 56 by a press fit, while the seal assembly iscompression fit into the module shell 58. In a preferred embodiment ofthe invention, the pins 75 are comprised of electrically conductivealloys, such as nickel & gold plated brass.

FIG. 4 is a plan view of the control module 40. FIG. 2 illustrates howthe module 40 seats in a void space 29 of handle 38. Pins 75 extendperpendicularly away from the lower part of the control module 40.

The control module 40, now described by initial reference to FIGS. 3-5,includes a housing that consists of a shell 58 and a lid 60. Both theshell 58 and lid 60 are formed from aluminum. In a preferred embodimentof this invention, the shell and the lid 60 are formed from aluminumalloy 7075 T6. This alloy has a yield strength of at least 420 MPa. Thecontrol module shell 58 houses a printed circuit board 59. The lid 60 isfastened to the top of the module 50 using a threaded fastener 55. TwoO-rings 61 and 62 are disposed between shell 58 and lid 60. Pins 75extend through openings 69 (FIG. 6A) in the shell 58. The pins 75provide conductive paths to/from the control components internal to themodule 40. A seal assembly 56 forms a set of individual seals around thepins 75.

Control module shell 58, seen best in FIGS. 5 and 17, has five panels, alower panel 53, a pair of side panels 51 and 52, a top panel 54, and abase panel 63. Base panel 63 is the largest of the panels, panels 51-54extend perpendicularly outwardly from the edges of the base panel 63.When the control module 40 is seated in the module shell 58, side panel52 is the most distal of the panels and extends longitudinally insidethe handle 38. Lower and top panels 53 and 54, respectively, extendperpendicularly rearward through the handle 38 from the opposed top andbottom edges of the side panel 52. Side panel 51 is the most proximal ofthe panels. The side panel 51 extends between the proximal ends of thelower and top panels 53 and 54, respectively. The side panel 52 extendsbetween the distal ends of the lower and top panels 53 and 54,respectively.

In the illustrated version of the invention, panels 51 and 52 have acommon thickness, the distance between the inner and outer faces, ofapproximately 1.4 mm. Top panel 54 has a thickness of approximately 1.9mm. Lower panel 53 has a thickness of approximately 6.35 mm. Shell 58 isformed so that two rows of openings 69 extend through lower panel 53.Each row of openings 69 contains 4 openings. Shell 58 is further shapedso as to have a step 102 within panels 51-54 that is recessed relativeto the outer rim of shell. Here, the outer rim is the coplanar faces ofthe panels 51-54 (rim not identified) that are directed towards lid 60.Step 102 extends circumferentially around the shell 58 and is recessedinwardly relative to the rim. The step 102 is spaced inwardly away fromthe outer edge of the shell rim. Sections of step 102, it shouldtherefore be appreciated, are formed in each one of the panels 51-54.

A post 57 is formed integrally with and extends outwardly from shellbase panel 63. Post 57 extends away from the inner face of base panel 63toward lid 60. Post 57 is cylindrical in shape. The post has a heightless than that of panels 51-54. The post 57 is formed to have a closedend threaded bore 97, as shown in FIG. 17, which extends inwardly fromthe outer circular face of the post (bore face not identified). Post 57is further formed so as to have an annular groove 65, as seen in FIGS. 6& 17, which extends inwardly from the face of the post. Groove 65 isthus located inwardly of the outer circular wall of the post 57 andoutwardly of the inner surface of the post that defines bore 97. Inanother embodiment of this invention, plural posts 57 are formallyintegrated with and extend outwardly from shell base panel 63.

Located internal to and formed integrally with shell 58 is a block 66.Block 66 is located inside the shell 58 in the corner where side panel52 and top panel 54 meet. Shell 58 is formed so that the block 66extends outwardly from the inner face of the base panel 63. The heightof the block 66 is less than the coequal height of the panels 51-54. Twokeys 67 and 68 extend distally forward from the outer face of shell sidepanel 52. Key 67 is circular in shape. Key 68 is rectangular in shape.As seen in FIG. 6, key 67 extends over side panel 52 from a locationspaced from top panel 54. Key 67 extends essentially outwardly from theouter face of the side panel 52 that is directly opposite the section ofthe inner face of the panel 52 against which block 66 abuts. The shell58 is further formed so that a closed-ended threaded bore 43 (seen inphantom in FIG. 17), extends inwardly from the exposed face of key 67,through the adjacent section of side panel 52 and into block 66. Key 68extends from the end of the side panel 51 that forms a corner edge withbottom panel 53. Key 68 extends along the side panel 52 a distance equalto approximately one-quarter the total length of the panel.

Control module shell 58 is also formed to have a tab 50. Tab 50 extendsaway from the outer face of side panel 51. Tab 50 is located immediatelyabove the bottom edge of panel 51, above lower panel 53. Tab 50 isformed with a triangular shape from the top view. In the illustratedversion of the invention, tab 50 is generally in the form of aright-angle triangle wherein the hypotenuse extends upwardly andoutwardly away from the shell bottom panel 51. The tab 50 is formed sothat in the outmost section there is a through opening (not identified).

As shown in FIGS. 5 and 7, lid 60 is formed as a single-piece unit andis shaped to have a panel 106. Panel 106 is in the form of a rectanglewith rounded corners. The panel 106 is dimensioned to slip fit in thevoid space defined by—shell panels 51-54. Two ribs 73 and 74 are formedintegrally with the panel 106. Ribs 73 and 74 extend downwardly from theopposed longitudinal edges of the panel 106. Each rib 73 and 74 extendslongitudinally along the panel 106. Each rib 73 and 74 is locatedinwardly of one of the longitudinal edges of the panel 106. Rib 73 isslightly shorter in length than rib 74. The difference in rib length isso that, when the lid is seated over the shell 58, the truncated end ofrib 73 can seat next to shell block 66.

Lid 60 is further formed to have a rim 104 that projects outwardly frompanel 106. Rim 104 extends outwardly around the outer perimeter of thepanel 106 and extends circumferentially around the panel 106. The addedlength and width of rim 104 provides lid 60 with a length and widthequal to the corresponding dimensions of the shell 58. The outer surfaceof rim 104 is coplanar with the outer surface of the lid panel 106. Thethickness of the rim 104 is less than that of panel 106. Consequently,on the inner side of the lid 60 here is a step (not identified) betweenthe inner surface of the rim 104 and the inner surface of panel 106.

A cylindrical boss 70 also extends downwardly from lid panel 106. Boss70 is positioned so that, when the lid 60 is disposed over shell 58, theboss 70 is aligned with the underlying shell post 57. Boss 70 has adiameter slightly greater than that of shell post 57. Boss 70 is formedto have an inner face that has a lip 71 that extends downwardly, towardsshell base panel 63. Lip 71 extends circumferentially around the outerperimeter of the inner face of the boss 70. Lip 71 which is ring-like inshape, has an inner diameter that facilitates the tight slip fitting ofthe lip 71 around shell post 57. Lid 60 is further formed so that a bore72 extends axially through boss 70 and the overlying section of lidpanel 106. Lid panel 106 has a tapered counterbore 108 that extendsinwardly towards and is centered around bore 72.

O-rings 61 and 62 are made from rubber/plastic such as fluoroelastomers.The material from which the O-rings 61 and 62 are formed must be able towithstand exposure to temperatures of at least 135° C. without breakingdown. One such material is a fluoroelastomer manufactured by SealsEastern, Inc. and sold under the trademark AFLAS. Both O-rings 61 and 62are circular in cross-section.

Inner O-ring 62 is circular in shape and is dimensioned to fit in groove65 formed in the exposed face of shell post 57. The outer diameter ofO-ring 62 is such that it extends approximately 0.25 mm above post 57.

Outer O-ring 61 is rectangular in shape and designed to seat over shellstep 102. O-ring 61 is designed to extend above the outer rim of shell58 by the same distance as O-ring 61 extends above post 57.

FIGS. 8 and 10-14 show the components of seal assembly 56. Specifically,the assembly includes a number of active seals 79. Each active seal 79extends between one of the pins and the circular inner wall of the shelllower panel 53 that defines the opening 69 through which the pinextends. An outer retaining cap 76 is press fitted into openings 69 ofthe lower panel 53. Outer retaining cap 76 is pressed over pins 75. Aninner retaining cap 77, also part of the seal assembly, is press fittedinto openings 69 of the lower panel 53. Retaining caps 76 and 77 holdactive seals 79 in openings 69. In one version of this invention, activeseal 79 is a polyimide energized seal.

FIGS. 11 and 12 illustrate the pin 75 over which electrical signals areconducted between the internal components of the control module 40 andthe external components. Each pin 75 has a D-shaped collar 80, a head82, and a shaft 83. The collar 80 projects radially beyond the end ofthe shaft 83. The head 82 has a closed-end bore 110. The shaft 83 iscomprised of three sections of decreasing diameter. There is a firstportion 84, the largest diameter section that extends inwardly fromcollar 80. A second portion 85 extends inwardly from the first portion84. A third portion 86 extends inwardly from the second portion 85. Thefirst portion 84 has a diameter that is larger than the diameter of thesecond portion 85. The second portion 85 has a diameter that is largerthan the diameter of third portion 86.

In the described version of the invention module 40 has eight pins 75.Two pins 75 are connected to the tool power source. One pin 75 each isconnected to each of the three phase windings internal to the tool motor34. The remaining three pins 75 serve as conductive members over whichcontrol and tool status signals are exchanged between the componentsinside the module 40 and those outside the module. Each pin 75 extendsthrough a separate one of the shell bores 69. In one embodiment of theinvention, at least one pin is used to generate the electricalconnection to components internal to module shell 58.

Shown in FIG. 13 is the parallelogram-shaped outer retaining cap, 76.Outer retaining cap 76 of FIG. 13 has a parallelogram-shaped outer capplate 91 with rounded corners (not identified). A plurality of capbosses 92, equal to the number of shell lower panel openings 69 extendinwardly from the inwardly directed face of plate 91, the face directedtowards shell 58. Bosses 92 have a diameter that facilitates the pressfit of the bosses 92 in the shell openings 69. A bore 90 extends axiallythrough the boss 92 and the section of the plate 91 from which the boreprojects. Bore 90 has a diameter that is a press fit relative to thediameter of pin shaft first portion 84. Rectangularly shaped tabs 81extend outwardly from the outwardly directed face of the outer cap plate91. Six tabs 81 extend outwardly from outer plate 91. Where two tabs 81are located on either side of bore 92 the tabs are spaced apart adistance slightly greater than the distance between the opposed parallelsides of a pin collar 80. When the control module 40 is assembled pincollars 80 are located adjacent to the tabs 81. The tabs 81 thus inhibitthe rotational movement of the pins 75.

Shown in FIG. 14 is the parallelogram-shaped inner retaining cap 77.Inner retaining cap 77 of FIG. 14 has a parallelogram-shaped inner capplate 93 with rounded corners (not identified). A plurality of capbosses 94, equal to the number of shell lower panel openings 69 extendoutwardly from the outwardly directed face of plate 93, the facedirected into shell 58. Bosses 94 have a diameter that facilitates thepress fit of the bosses 94 in the shell openings 69. An inner cap bore95 extends axially through the cap boss 94 and the section of the plate93 from which the bore projects. Bore 95 has a diameter that is a pressfit relative to the diameter of pin shaft second portion 85. Pin shaftthird section 86 is slip fit through the entire seal assembly 56.

Each active seal 79, one seen in FIG. 18, includes a boot 120 and aspring 130. Boot 120 is formed from PTFE sold under the trademark Teflonor another material that has both some degree of flexibility andcapability of withstanding the rigors of autoclave sterilization. Theboot 120 must also be able to not melt when exposed to the heatassociated with soldering wires to pins 75. The boot 120 is generallyringlike in shape. The boot 120 has a base 122 that, in cross section,appears rectangularly shaped. Two spaced apart, ring-shaped skirts 124and 126 extend away from the opposed inner and outer sections of thebase 122. Both skirts 124 and 126 extend generally away from theoutwardly directed face of boot base 122. Skirt 124, the inner skirt,also extends slightly radially inwardly from the inner annular face ofthe base 122. Skirt 126, the outer skirt, extends slightly radiallyoutwardly from the outer annular face of the base 122.

Owing to the spacing apart of the skirts 124 and 126, there is anannular gap (not identified) above the base 122, between the skirts 124and 126.

Spring 130 is formed from a nickel-chromium-based alloy sold under thetrademark Inconel. This material, like boot 120, is capable ofwithstanding the sterilization of tool 30. The metal forming spring 130is helically wound. Spring 130 is seated in the annular gap between theboot skirts 124 and 126. The spring 130 has a diameter that is greaterthan the width across the gap between the skirts. For example, if thisgap has a relaxed width of 1.0 mm, the spring has a diameter of 1.1 mm.In alternative versions of the invention, spring 130 may be replacedwith a biasing member that replicates the biasing force of spring 130.

Spring 130 imposes a biasing force on the skirts that cause inner skirt124 to bow inwardly, toward the center of the boot 120, and outer skirt126 to bow outwardly, away from the center of the boot. Collectively,boot 120 and spring 130 are selected so that, when the active seal isassembled, the distance between the outer surfaces of the boot skirt 124and 126 is greater than the annular gap present between the section ofthe pin 75 disposed in the shell bore 69 and the adjacent bore-defininginner surface of the shell 58. In the described version of theinvention, the active seal is disposed around the pin stem secondportion 85. Inner skirt 124 presses against this pin portion. Outerskirt 126 presses against the surrounding annular wall of the shell 58that defines bore 69. This portion of the pin 75 has a diameter ofapproximately 1.530 mm. Shell bore 69 has a diameter of approximately4.43 mm. The distance across the bowed boot skirts 124 and 126 isapproximately 1.46 mm.

Printed circuit board 59 contains the components 140 used to regulatethe application of power to the tool power generating unit, motor 34.The exact structure of the components 140 is a function of the powergenerating unit integral with the tool. Therefore, the structure ofthese components is not material to this invention. When the powergenerating unit is a motor, the circuit described in the incorporated byreference U.S. Pat. No. 7,638,958 may be built onto circuit board 59.These components include first and second sets of sensors (notillustrated). The first set of sensors monitor the actuation of thetrigger switches 46 and 47. The second set of sensors monitors the stateof the tool motor. To facilitate the responsiveness of the sensors,portions of the shell 58 may be formed from material through which thephysical quantity (quantities) monitored by the sensors can pass. Forexample, if one or more of the sensors monitors a magnetic field(fields) adjacent sections of the shell may be formed from combinationsof magnetic and nonmagnetic material that focuses the field (fields). Ifthe sensors monitor photonic energy (light) the shell 58 may have panelsor sections of panels that are transparent to the wavelength of themonitored light.

Printed circuit board 59 is formed with an opening 138. When the circuitboard 59 is seated in the housing shell 58, the shell post 57 extendsthrough opening 138.

Control module 40 is first assembled by press fitting pins 75 into capbores 90 of outer retaining cap 76. More particularly, the pin stemfirst portions 84 are press fit in cap bores 90 so that the remainingportions of the pin stems extend out through bosses 92. Active seals 79are then inserted over the pin stem second portions 85. Outer retainingcap 76 is then press fit to the lower panel 53 of shell 58 so thatbosses 92 seat in shell bores 69. Each active seal 79 is fitted in theassociated shell bore 69 so that, as seen in FIG. 8, the free ends ofthe boot skirts 124 and 126 are directed towards the adjacent outerretainer cap boss 92. When each seal is so positioned, the spring 130simultaneously causes boot skirt 124 to press against the pin stemsecond portion 85 and boot skirt 126 to press against the inner circularwall of the shell 58 that defines the bore 69. Each seal 79 thusfunctions as a substantially gas-tight seal between each pin 75 and thesurrounding portion of the shell bore 69.

The inner retainer cap 77 is then fit over the inner face of the shelllower panel 53 and the pins 75. Owing to the relative dimension of thepins 75 and boss bores 95, the cap bosses 94 initially are slip fit overthe pin third shaft section 86. Then, the cap bosses 94 aresimultaneously press fit into the lower panel openings 69 and over thepin second shaft section 85. The components forming seal assembly 56 arefurther configured, so that when assembled, the active seals 79 are notcompressed between the opposed cap bosses 92 and 94. Instead, even withseals 79 disposed in a bore 69, there is space within each shell bore 69for the active seal 79 to move between the cap bosses 92 and 94. In thedescribed version of the invention, wherein the shell bore 69 has alength of 6.35 mm and a diameter of 4.43 mm, this distance isapproximately 1.91 mm. When the seal assembly 56 is mounted to the shell58, the pin third portions 86 extend beyond inner cap plate 93 into theshell 58.

Once seal assembly 56 is mounted to shell 58, circuit board 59 is fittedon top of base panel 63 of module shell 58. In the described version ofthe invention, the circuit board 59 is fit below the two rows of pins.Contacts on the circuit board 59, not illustrated and not part of thisinvention, establish mechanical and conductive connections between thebottom row of pins 75. Pins 75 create mechanical and conductiveconnections between the exposed pin portions 86 adjacent the top of theboard and the components on the board. Solder and wire connections, notillustrated and not part of this invention, may be used to establishconductive paths between the pins 75 that extend over the circuit board59 and the complementary board components.

Fasteners or adhesive, not illustrated and not part of this invention,are used to hold the circuit board in the shell 58.

Once the circuit board 59 is in place, assembly of the control module iscompleted by the securement of the lid 60 to the shell 58. This processstarts with the seating of O-ring 61 over module step 102. O-ring 62 isseated in the post groove 65. Lid 60 is then fitted over the open end ofshell 58. Owing to the dimensioning of the components, there is a closeslip fit between the outer surface of each lid rib 73 and 74 and theinner surface of, respectively, the adjacent side panel 52 and 51. Theclearance between each rib 73 and 74 and adjacent side panel may beapproximately 0.05 mm. As a consequence of the fitting of the lid 60over the shell, the lid boss 70 seats over shell post 57. Moreparticularly, lip 71 integral with lid boss 70 is fit around the outerperimeter of the post 57.

Fastener 55 is then used to secure the lid 60 to the shell 58. Fastener55 is also secured to the lid 60 with an adhesive manufactured by theHenkel Company and sold under the trademark Loctite. The fastener isinserted through lid bore 72 and threaded into shell post bore 97. Whentightened, the fastener 55 presses the lid 60 against the shell 58. As aresult of this movement, O-ring 61 is compressed between the shell step102 and the lid rim 104. O-ring 62 is compressed between the shell postgroove 65 and the face of lid boss 70 so that lid boss 70 provides aface seal. As a consequence of the compression of the O-rings 61 and 62,the O-rings form substantially gas-tight seals between the modulehousingforming shell 58 and lid 60.

The assembled control module 40 is then inserted into handle void space29. Keys 67 and 68 serve as spacers to ensure the control module 40 isproperly positioned in the handle 38. Key 68 also serves to transferheat generated by the internal electrical components of control module40. Heat dissipated from the shell 58 transfers through key 68 and intothe handle 38. Fasteners, not illustrated, hold the control module 40 tothe handle 38. One fastener extends through closed-ended threaded bore43 of key 67 into block 66 to anchor module 40 to the handle 38. Asecond fastener extends through the opening in tab 50 to an adjacentstructural member internal to the tool handle 38. Tab 50 is angled toforce control module 40 into the handle 38. Once the control module 40is secured to the rest of the tool 30, the appropriate conductors (notillustrated) are attached to the exposed pin heads 82. Each conductor issolder secured into the closed-end bores 110 internal to the pin head82, as shown in FIG. 10.

Once the tool 30 is completely assembled, the tool is ready for use. Thetool is used like a conventional tool. A medical practitioner depressesone of the trigger switches 46 or 47. This motion is detected by thecircuit internal to module 40. The circuit then causes the appropriateenergization signals to be applied to the motor 34. This results in thecutting accessory being actuated in order to perform the desiredmedical/surgical procedure.

Once tool 30 is used, the tool can be autoclave sterilized like aconventional tool. In this process, the tool is placed in a sealedchamber into which saturated steam is introduced at temperatures up to135° C. and pressures as high as 305,000 Pa absolute. During thisprocess, the highly pressured steam presses against the outside of themodule housing. A 686 mm of Mercury vacuum is then drawn on thehandpiece. The seal-forming O-rings 61 and 62 prevent essentially anyleakage of the highly pressurized steam into the control module 40.During the steam pressurization cycle, the pressurized steam pressesinwardly on the structural members of the module housing, shell panels51-54 and 63, and lid 60. The differential pressures between the insideand outside of the module housing results in the inward flexing of thehousing panels, especially the lid 60 and the shell base panel 63. Thisinward flexing of the lid 60 is opposed by the abutment of the shellpost 57 against the lid. During the vacuum drawing cycle, thedifferential pressure results in the outward flexing of the panelsforming the housing. This outward flexing of the lid 60 is opposed bythe ribs 73 and 74 and the fastener 55. The inhibiting of this outwardflexing of the shell 58 and the lid 60 reduces the displacement of thelid 60 away from outer O-ring 61 and the breaking of the sealestablished by the lid-against O-ring contact.

During sterilization, the seals 79 function as substantially gas-tightbarriers between the bore 69 defining walls of the shell lower panel 53and pins 75. It should be appreciated that during the sterilizationprocess, the module shell 58 and pins 75 undergo some thermal expansion.Thermal coefficients of expansion of the materials forming module shell58 and pins 75 are different. Pin 75 has a lower thermal coefficient ofexpansion than the surrounding shell 58. Consequently, there is anincrease in the width of the annular gap between each pin 75 andsurrounding shell wall. In response to this change, each seal spring 130pushes the adjacent boot skirts 124 and 126 outwardly away from eachother. Thus, each seal 79 maintains the barrier between the shell 58 andassociated pin 75 during this portion of the autoclave process. Alsoduring this portion of the autoclave process, a fraction of thepressurized steam may flow into the annular space between each pair ofseal skirts 124 and 126. This pressurized steam thus functions as asecond force that pushes the skirts 124 and 126 outwardly away from eachother so as to further enhance the tightness of the substantiallygas-tight seal.

Even with this deformation of the boot 120, skirt 124 still abuts pin 75and skirt 126 still abuts the surrounding inner wall of the shell lowerpanel 53. Each seal 79 therefore maintains a barrier around the pin 75over which the seal is seated. Further, this deformation of the sealalso means that thermal expansion of the shell 58 and pin 75 are notopposed by any forces that could impose fracture-inducing stresses onthese components.

During this process, the outward pushing of the seal skirts 124 and 126away from each other causes a lengthening of the skirts. The skirts areable to expand into the clearance space in the bore 69 between capbosses 92 and 94. This ability of the skirts 124 and 126 to freelyexpand allows the boots 120 to maintain their integrity.

Once tool 30 is sterilized, the tool is removed from the autoclave. Thetemperature of the tool returns back to ambient levels. At this time,shell 58 and pins 75 undergo thermal contraction. In response to thedecreasing in size of these components, the width of the annular gapbetween each pin 75 and the surrounding shell wall decreases. Thiscauses a like decrease in the distance between the boot skirts 124 and126. Each spring 130 is therefore subject to some radial compression.Owing to their flexible nature, springs 130 are able to undergo thiscompression without plastically mechanically deforming. Consequently,each spring 130 is still able to impose force on the associated bootthat holds the skirts 124 and 126 away from each other. Springs 130 arethus able to supply the forces needed to maintain seals around pins 75as the tool is, over time, subjected to plural autoclave sterilizations.

Tool 30 of this invention has a control module with sets of seals ableto withstand the rigors of repeated autoclave sterilization. O-rings 61and 62 stop steam from entering between the module 40 between the shell58 and lid 60. Due to the same material used in forming shell 58 and lid60, creating equal coefficients of thermal expansion, O-rings are ableto be used. Seal assembly 56 blocks steam from entering the controlmodule 40 through shell bores 69. Both these sets of seals arerelatively economical to provide.

Further, shell 58 and lid 60 have features, shell post 57 and lid ribs73 and 74 that inhibit the flexing of the control module housing whenthe tool 30 is pressurized during sterilization. By increasing thestiffness of the lid 60, the risk of having the seal broken is reduced.

Another benefit of tool 30 of this invention over a tool with a controlmodule that is brazed or welded closed is that it is possible to easilyopen module 40. This is accomplished by unscrewing fastener 55 and thenremoving lid 60. Thus, one could periodically remove the lid 60 from theshell 58. This process can be performed in a very dry (low humidity)work environment in order to facilitate the evaporation of any waterthat may have worked itself into the module housing. The componentsinternal to the module can be inspected to determine if there is anyevidence of potentially failure-inducing corrosion. Prior to resecuringof the lid 60 to the shell 58, the housing can be provided with newO-rings 61 and 62. Thus, unlike some present control modules, thecontrol module of this invention is designed to allow preventivemaintenance and repair. This can avoid the more costly process of havingto periodically provide the tool with a completely new control module.

II. Alternative Embodiments

The above description is directed to one version of the invention. Otherversions of the invention may have features different from what has beendescribed.

For example, there is no requirement that all versions of the inventioncontain both the described seal assembly 56 and O-rings 61 and 62. Otherversions of this invention may only have a single one of the features.

In some versions of the invention, the O-rings 61 and/or 62 may bereplaced with an active seal similar to active seal 79. Each active sealwould have a boot sized to fit between where the cover and lid wouldotherwise abut. Internal to the boot is one or more biasing componentssimilar to seal spring 130 that exert a force on the boot skirts. Theseactive seals would be similar in shape and size to the O-rings 61 and62. These active seals would provide the function of the active seal 79in the location of current O-rings 61 and 62. In other versions of theinvention, O-rings 61 and/or 62 may be replaced with a gasket or amaterial similarly capable of establishing a substantially gas-tightseal between the structural members of the control module. The sealfunction performed by both O-rings 61 and 62 may be performed by asingle piece of an elastomeric material. This piece of elastomericmaterial is positioned so as to extend between both the shell rim-to-lidinterface and the post-to-lid interface.

In these as well as other embodiments of the invention, it may not benecessary to provide the module shell with an inwardly directed stepagainst which the rim-to-lid seal seats. Thus, in these versions of theinvention, the rim-to-lid seal may directly abut the outer most face ofthe shell rim.

In alternative versions of the invention, components other than the capbosses may serves as the stops that prevent longitudinal movement of theactive seals out of the module panel in which they are seated. There isno requirement that a plurality of cap bosses for either the innerretaining cap or outer retaining cap extend from a common plate. Inthese versions of the invention, associated with each active seal, arean inner stop and an outer stop. Neither of these stops are connected toany of the other stops that may be fitted to the common module panel.This is especially true in versions of the invention in which theconductive pins that extend through the control module are either widelyspaced apart from each other (0.5 cm or more) or extend throughdifferent panels in the control module.

Further, this invention is not limited to seal assemblies wherein thestops are rigid cylindrical members that are simply pressed into thepanel opening in which they are seated. One such alternative stop 125,now described by reference to FIG. 18A. First stop 125 and active seal127 are a single piece of rubber. Stop 125 may be integrally formed as aportion of the active seal 127 so as to tightly fit against the boredefining inner wall of lower panel 53. First stop 125 is acircumferential step or ring located inwardly from the bore defininginner wall of lower panel 53. Stop 125 and seal 127 are disposed arounda conductive pin 75. A spring 130 is disposed between the seal bootskirts (not identified). Not illustrated in FIG. 18A is a second stop.

In alternative versions of the invention, a first stop 128 maybeintegrally formed with the panel 53 itself, as shown in FIG. 18B. Stop128 is comprised of the same material as panel 53. In these versions ofthe invention, the stop 128 consists of a circumferential ring or stepthat is part of the panel that extends inwardly into the bore defininginner wall of lower panel 53 in which the conductive pin 75 and activeseal 79 are seated. This ring or step may be flush with either the outeror inner walls of the lower panel 53 and act as either an inner or outerstop. Alternatively, this ring or step may be recessed relative to theinner or outer wall of the lower panel 53. Not illustrated in FIG. 18Bis the active seal 79 or conductive pin 75.

In some versions of the invention, a compression ring 129, as shown inFIG. 18B, may function as one, if not both, of the inner or outer stops.In these versions of the invention, the compression ring 129 forms thestop (or plug) function. It may be necessary to provide a panel 53 withan annular groove (not identified) that extends outwardly from the boredefining inner wall of lower panel 53. The outer perimeter or surface ofthe compression ring 129 seats or snaps into the annular groove.

These various alternative features may also be combined. For example,the compression ring or stop may be integrally formed with the activeseal upon assembly of the module. The outer perimeter of the compressionring portion is snap fit into the groove formed in the bore defininginner wall of lower panel 53.

Likewise, in some versions of the invention, the features that inhibitrotation of the conductive pins may be formed with the inner stops.

Similarly, this invention is not limited to battery powered motorizedsurgical tools. In other versions of the invention, the tool thatreceives power over a cable connected to a control console. In otherversions of the invention, the power generating unit may be a devicethat generates electrical energy, thermal energy or photonic energy.Other tools may generate other forms of mechanical energy, such as toolsdesigned to vibrate the attached cutting accessory.

In other versions of the invention, the tool may not have the shellabutting post. Still other versions of the invention may have pluralshell abutting posts. In these versions of the invention, less than allof the posts may be provided with features to facilitate the securementof the overlying lid to the post.

Similarly, there is no requirement that in all versions of theinvention, the lid be provided with the two described stiffening ribs.In some versions of the invention, the lid may have only a singlestiffening rib. Likewise in some versions of the invention, it may bedesirable to provide the lid with three or more stiffening ribs.Similarly, there is no requirement that in all versions of the inventionthe ribs be simple linear structures. Other versions of the inventionmay have ribs with non-linear shapes.

Likewise, seal assembly 56 may have other constructions than what hasbeen described. As mentioned above, the actual number of active seals isa function of the number of pins required to provide conductive pathsto/from the control module. If there was no need to provide the modulewith pins to establish external communications links, fewer pins andcompanion seals are needed. A tool with sensors located outside of thecontrol module may require more pins and, therefore, more seals. When apin seal of this invention is provided there is no requirement that asingle inner or outer retainer hold all the active seals 79 in place. Insome versions of the invention, a pair of companion inner and outerretainers may hold a single active seal 79 in position.

Likewise, in some versions of the invention, the construction of thetool may necessitate that the pins that extend into the module housingbe grouped together. In some versions of the invention, one set of pinsmay extend through a first one of the housing panels while a second setof pins extends through a separate housing panel. Thus, in this andother versions of the invention, a tool of this invention may haveplural spaced apart seal assemblies 56, each of which includes one ormore active seals.

Unless recited in the claims, the stated dimensions are for purposes ofillustration only.

Likewise, while the module of this invention is designed for use with asurgical tool, its use is not limited to this type of tool. The modulemay be used to seal components contained in other devices. For example,the module can be used to seal components used in marine or aerospaceenvironments. Further, the module may not only be used to housecomponents used to regulate the operation of a tool. In alternativeapplications, the module of this invention may be used to housecomponents used to perform functions other than those that control apower generating unit. For example, in one marine application, themodule of this invention may be used for housing components used toprocess signals received/transmitted from a sonar transducer. Thus, itis an object of the appended claims to cover all such variations andmodifications that come within the true spirit and scope of thisinvention.

Likewise, the sealed control module 40 of this invention may also bedesigned to facilitate the assembly of the module 40 and its internalcomponents. In this version of the invention, seen in FIG. 19, a spacer144 is attached on a surface of a control board 142, a printed circuitboard. A mount 160 holds a plurality of Hall sensors 162, 164, 166 and168 to the printed circuit board 142 within the module 40. Mount 160,along with spacer 144, align internal components in all three axesduring and after manufacture.

In this version of the module 40, a printed circuit board 142 contains aplurality of analog Hall sensors 162, 164 and 166 used to regulate theapplication of power to the tool power generating unit, motor 34, or tobe actuated by trigger switches 46, 47, now described by reference toFIGS. 1, 2 and 19. A sensor 168 is a digital Hall sensor. The positionof analog Hall sensors 162, 164 is a function of the location of thepower generating unit integral with the tool. When the power generatingunit is a motor, the circuit described in the incorporated by referenceU.S. Pat. No. 7,638,958 may be built onto circuit board 142.

Each analog sensor is comprised of a body (not identified) and aplurality of electrical leads (not identified) that extend away from thebody. Analog sensors 162 and 164 facilitate regulation of theapplication of power to the motor rotor, 34. Sensor 164 has longerelectrical leads than sensor 162 for manufacturing reasons. Each analogsensor 166 and digital Hall sensor 168 pair is used to regulate theapplication of power to the motor proportional to the position of anassociated tool trigger switch 46 or 47. Applicant's Assignee's U.S.Pat. No. 7,638,958, incorporated herein by reference, discloses oneanalog Hall sensor/digital Hall sensor for powering the motor 34 ortriggers 46, 47.

Mount 160 is comprised of a single piece of plastic. Mount 160 iscomprised of three sections: a base 170, an L-shaped section 172, and aH-shaped section 174, now described by reference to FIGS. 20 and 21.Base 170 has opposed ends (not identified). On each end of base 170 is apair of spaced apart side walls 171 defining a pair of slots 176. Aconnecting section 173 connects each side wall 171 with each an opposingside wall 171. Side walls 171 extend above the height of base 170. Sidewalls 171 are approximately equal in height. Each slot 176 is locatedforward of connecting section 173. On the top surface of base 170 is apedestal 188. Pedestal 188 is rectangular in shape and extends from thesurface of base 170. Pedestal 188 is located on the rear of the base 170and equally spaced between opposed ends of base 170. Extending from atop surface of pedestal 188 is a post 186. Post 186 is circular in shapeand has an approximate diameter of 1.4 mm. Connected adjacent to base170 is the L-shaped section 172. L-shaped section 172 extends away fromone end of base 170. L-shaped section 172 is attached to base 170 so asto be aligned with the adjacent connecting section 173. Located on oneend of L-shaped section 172 is a pedestal 184. Pedestal 184 isrectangular in shape and extends from a top surface of L-shaped section172. Pedestal 184 is approximately equal in cross-dimension to pedestal188. Extending away from a top surface of pedestal 184 is a post 182.Post 182 is circular in shape and has a diameter equal to the diameterof post 186. Located on opposed end of L-shaped section 172 is apedestal 180. Pedestal 180 is C-shaped and extends from the top surfaceof L-shaped section 172. Pedestal 180 is smaller in cross-dimension thanpedestals 184 and 188. Extending away from a top surface of pedestal 180is a post 178. Post 178 is smaller in diameter than posts 182 and 186.Connected adjacent to pedestal 180 of L-shaped section 172 is H-shapedsection 174. H-shaped section 174 has a pair of opposed parallel spacedapart walls 175. Walls 175 comprise the opposed ends of H-shaped section174. Connecting walls 175 is a cross-beam 177. Beam 177 is approximatelylinear with L-shaped section 172 and base 170. Walls 175 with beam 177define a pair of slots 176. Each slot 176 is dimensioned to seat thebody of an analog Hall sensor 162, 164 and 166 or the body of a digitalHall sensor 168, as shown by FIG. 19.

Pedestals 180, 184, and 188 extend to the same height above base 170 soas to form a plane to bottom out against a bottom surface of circuitboard 142. Posts 178, 182 and 186 also extend to the same height abovebase 170 so as to form a plane.

A spacer 144, now described by reference to FIG. 22, is comprised of asingle piece of plastic. Spacer is approximately 1.4 mm thick. Spacer144 has a pair of through bores 146 and 148. Spacer through bores 146and 148 are slightly larger in diameter to mount posts 182 and 186,respectively. Spacer 144 further includes a circular bore 150 and anL-shaped bore 152. Bore 150 is approximately the same diameter as anopening 158 of printed circuit board 142 (and opening 138 of printedcircuit board 59), as shown in FIGS. 22, and 23. Bore 152 providesclearance for components, such as a capacitor (not identified) attachedto the top surface of printed circuit board 142. The exact location ofbore 152 is not defined and is a function of external components on theprinted circuit board 142 requiring clearance during final assembly.

Printed circuit board 142 is now further described by reference to FIG.23. In some versions of this invention, printed circuit board 142 ofcontrol module 40 may be replaced with previously disclosed printedcircuit board 59, as shown in FIG. 5. In some versions of thisinvention, both printed circuit board 142 and printed circuit board 59are present. Extending from a top edge of circuit board 142 arepeninsulas 155 and 157. Each peninsula contains three equally spacedapart holes (not identified) for accepting the electrical leads of aHall sensor 168. The three electrical leads of each sensor 168 are slipfit through the three peninsula holes. Sensors are attached to thecircuit board 142 with mount 160. Sensors leads are soldered to theboard. Printed circuit board 142 is further formed with an opening 158.Circuit board 142 further includes bores 149, 154 and 156. Bore 149 islocated on a side edge of printed circuit board 142. Bore 149 isslightly larger in diameter than mount post 178. Bores 154 and 156 areslightly larger in diameter than mount posts 186 and 182, respectively.Each circuit board bore is slightly larger than its respective post inorder to provide a clearance. This clearance is created formanufacturing reasons so that an adhesive can attach the circuit boardover the mount posts. Mount 160 is secured to printed circuit board 142using the post-in-bore arrangement seen in FIG. 19.

Shown in FIG. 24 is a lid 179. Lid 179 is an alternative embodiment ofpreviously described lid 60 of this invention. Lid 179 is formed withall the features of lid 60.

A bottom surface of lid 179 includes a plurality of closed-end recesses181. The shape and depth of each recess 181 is a function of the type ofcomponent located on the top surface of printed circuit board 142. Eachrecess 181 is dimensioned to provide clearance for an associated circuitboard component, for manufacturing reasons. Recessed bores 183 and 185are further formed on lid 179 and are close-ended. Each bore 183 isdimensioned to receive mount post 178 within the bottom surface of lid179. Bores 185 are dimensioned to receive mount posts 182 and 186 withinthe bottom surface of lid 179. Cut-outs 187 are recesses withinpreviously-described rib 73 of this invention. Cut-outs 187 are cut fromrib 73 to allow clearance for each associated circuit board peninsula155 and 157. During final assembly, circuit board peninsulas 155 and 157seat within lid cut-outs 187.

Mount 160 is fitted with sensors 162, 164 and 166 by placing mount 160in a fixture. Once mount 160 is seated in the fixture, sensors 162 and166 are seated within the associated mount slots 176, as shown in FIG.19. Sensor 162 is seated within the upper slot 176 of H-shaped section174. Digital sensors 168 are then seated within associated mounts slots176. Sensors are inserted either by hand or by tweezers. The electricalleads of each sensor are pre-bent and cut so they slip fit into thecircuit board 142. The electrical leads of motor rotor analog Hallsensors 162 and 164 are longer for manufacturing and packaging reasons.

An adhesive is next applied around the openings of the printed circuitboard 142 where mount posts 178, 182, 186 are slip fit through. AnalogHall sensor 164 is seated within mount slot 176 of H-shaped section 174.Printed circuit board 142 is fitted over mount 160. In this process, theboard 142 is fitted over the sensor leads so that the sensor leads seatin the corresponding openings in the board. The sensor leads aresoldered to the board. Soldering bonds the outer surfaces of electricalleads to the circuit board 142. Simultaneously, mount post 178 is slipfit through circuit board bore 149, and mount posts 182 and 186 are slipfit through circuit board bores 154 and 156, respectively. Industrialadhesive is applied around the outer surface of each post to securemount 160 to spacer 144. Owing to the clearance between each post andassociated board bore, adhesive enters the space between an outersurface of each post and an inner wall of each board bore to create astronger bond. Since three points define a plane, mount posts orient theHall sensors to the lid 179, and then the control module 40. Mount postsassist in controlling the “X” and “Y” components with respect to thepositioning of each sensor and the mount within the overall assembly.Spacer 144 controls the “Z” component with respect to the positioning ofeach sensor and the mount in the overall assembly.

Adhesive is then applied at select points along the top surface of thecircuit board 142, and spacer 144 is fastened to the top of circuitboard 142. Simultaneously, posts 182 and 186 are slip fit through spacerbores 146 and 148, respectively. Bores 146 and 148 assist in the properorientation of the spacer with respect to the circuit board 142 andadditional internal components of the control module 40.

Adhesive is then applied along the top surface of the spacer 144.Adhesive is also applied to the top face of each post 178, 182 and 186.Assembly is now secured within the bottom surface of lid 179. Spacer 144is now attached to the control module lid 179. The top surface of spacer144 abuts the bottom surface of lid 179. The top surface of post 178approaches, but does not abut, the bottom surface of lid at the locationof circular recess 183. The top surfaces of posts 182 and 186approaches, but does not abut, the bottom surface of lid 179 at thelocation of circular recesses 185.

When the spacer 144 is seated in the bottom surface of lid 179, thecircuit board, mount, and sensors, together as a sub-assembly, are nowsecured to the lid 179. Lid 179, with sub-assembly including: spacer,circuit board, mount and sensors, is then attached over a top opening ofmodule shell 58. Furthermore, shell post 57 extends through opening 158and spacer opening 150.

Consequently, analog Hall sensors 162, 164 and 166 and digital Hallsensors 168 are, by virtue of the mount 160, attached and properlyoriented to the control module lid 179 and properly oriented within thecontrol module 40. As a result. Hall sensors 162 and 164 are positionedtowards the motor rotor 34. Each pair of Hall sensors 166 and 168 arepositioned towards the surgical tool trigger switches 46, 47.

Another benefit of mount 160 is for ease of calibration after final toolassembly. When the powered surgical tool of this invention reaches itsfinal point of assembly, the handpiece is calibrated for accuracy. Aspart of this process, the signals output by the sensors are evaluated todetermine if they are within certain predetermined performanceparameters. Mount 160 secures each sensor to the circuit board 142 sothat the sensors may spatially fall within the required mechanical zonefor successful calibration. The mount 160 of this invention preventseach mounted Hall sensor from being displaced during, and after, allassembly stages; therefore, the surgical power tool is able to undergocalibration with greater efficacy and ease. In utilizing a mount toretain sensors in predetermined positions within the control module, themanufacturing scrap rate is minimized due to fewer failed calibrations.Another benefit of mount 160 is that it allows for an inexpensiveassembly process during manufacture. Mount 160 also provides for aspatially repeatable and reliable assembly of internal components.

In some versions of this invention, any one of mount posts 178, 182 or186 can extend from any inner surface of the control module 40. It isnot necessary that each post extend from the mount 160. In one versionof this invention, at least one post extends from the mount 160.

It should also be appreciated that alternative methods of assembling thecontrol module are within the scope of this invention. For example, insome versions of the invention the mount, with or without the sensorsalready fitted to the mount, is securely fitted to the control modulebefore the sensors are attached to the circuit board.

Likewise, there is no requirement that the mount always be secured tothe lid of the control module. In alternative versions of the invention,the mount may be secured to the inner surface of another panel thatdefines the void space of the control module.

Accordingly, it is an object of the following claims to cover all suchmodifications and variations that come within the true spirit and scopeof this invention.

What is claimed is:
 1. A control module for a powered surgical toolcomprising a housing, an attachment that extends from the housing forperforming a surgical/medical task, and a power generating unit disposedin the housing and connected to the attachment for actuating theattachment, the control module comprising: a shell formed from at leastone panel; a circuit board; at least one sensor disposed in the shellable to monitor an activity outside of the shell that is transmittedthrough a panel of the shell and that outputs a signal representative ofthe monitored activity to the circuit board; and a mount having a baseshaped to define at least one slot, the slot being dimensioned so thatthe sensor can closely slip fit in the slot.
 2. The control module ofclaim 1, further comprising a lid, a spacer, and an adhesive securingthe mount to the spacer, wherein the spacer positions the mount and thecircuit board away from a bottom surface of the lid.
 3. The controlmodule of claim 1 further comprising at least one post that extends fromthe base.
 4. The control module of claim 3, wherein the at least onepost is mounted to the circuit board.
 5. The control module of claim 4,wherein the at least one post is attached to the circuit board by anadhesive.
 6. The control module of claim 1, wherein the at least onesensor is seated in the at least one slot formed in the base.
 7. Thecontrol module of claim 6, wherein the mount holds the at least onesensor away from an outside perimeter of the circuit board.
 8. Thecontrol module of claim 1, the base comprising at least two slots thatare in tandem at the base.
 9. The control module of claim 1, wherein thebase is formed to define two slots that are co-planar so that thesensors in the slots are co-planar.
 10. The control module of claim 1,wherein the at least one sensor comprises one of a Watt sensor, acurrent sensor, a rotation sensor, a torque sensor, a force sensor, anda Hall effect sensor.
 11. A control module for a powered surgical toolcomprising a housing, an attachment that extends from the housing forperforming a surgical/medical task, and a power generating unit disposedin the housing and connected to the attachment for actuating theattachment, the control module comprising: a shell formed from at leastone panel; a circuit board; at least one Hall effect sensor disposed inthe shell able to monitor an activity outside of the shell that istransmitted through a panel of the shell and that outputs a signalrepresentative of the monitored activity to the circuit board; and amount configured to retain the at least one Hall effect sensor in apre-determined position within said control module.
 12. The controlmodule of claim 11, further comprising at least one post that extendsfrom the base.
 13. The control module of claim 12, wherein the at leastone post is mounted to the circuit board.
 14. The control module ofclaim 13, wherein the at least one post is attached to the circuit boardby an adhesive.
 15. A method of assembling a control module for apowered surgical tool, the control module that defines a void space inwhich there is a circuit board and at least one sensor, the methodincluding the steps of: providing a mount, the mount having a slot forreceiving a sensor; fitting the sensor in the slot; connecting thesensor to the circuit board; and positioning the mount so that the atleast one sensor is located at a defined location within the controlmodule void space.
 16. The method of claim 15, wherein the step ofproviding the mount comprises the mount having at least one post. 17.The method of claim 16, wherein the step of positioning the mountcomprises an end of the at least one post extending from a definedlocation on an interior surface of the control module.
 18. The method ofclaim 16, wherein the step of positioning the mount comprisespositioning a free end of the at least one post in an indentation thatextends inwardly from an inner surface of the control module.
 19. Themethod of claim 16, wherein, during the step of positioning the mount,the at least one post is seated in an opening formed in a spacer. 20.The method of claim 16, further comprising the step of positioning theat least one post in an opening formed in the circuit board.
 21. Themethod of claim 15, wherein after the step of fitting the sensor in theslot, the step of connecting the sensor to the circuit board isperformed.